package leetcode;

import java.util.HashSet;
import java.util.Scanner;

public class LeetCodeMain75 {
    public static void main2(String[] args) {
        Scanner in=new Scanner(System.in);
        while (in.hasNext()){
            String str=in.nextLine();
            String string=in.nextLine();
            HashSet<String> set=new HashSet<>();
            if (!str.contains("\"")){
                for (String string1:str.split(",")) {
                    set.add(string1);
                }
                if (set.contains(string)){
                    System.out.println("Ignore");
                }else {
                    System.out.println("Important!");
                }
            }else {
                StringBuffer buffer=new StringBuffer();
                int flag=0;
                for (int i = 0; i < str.length(); i++) {
                    char ch=str.charAt(i);
                    if (ch==','&&flag==0){
                        continue;
                    }if (ch=='"'){
                        if (flag==0){
                            flag++;
                        }else {
                            flag=0;
                            set.add(buffer.toString());
                            buffer.delete(0,buffer.length());
                        }
                    }else {
                        buffer.append(ch);
                    }
                }
                if (buffer.length()!=0){
                    set.add(buffer.toString());
                }
                if (set.contains(string)){
                    System.out.println("Ignore");
                }else {
                    System.out.println("Important!");
                }
            }
        }
    }

        public static void main(String[] args) {
            Scanner in = new Scanner(System.in);
            while (in.hasNext()){
                int n = in.nextInt();
                float fenmu = denominator(n);
                float fenzi = misSort(n);
                float result = (fenzi / fenmu) * 100;
                System.out.println(String.format("%.2f",result) + "%");
            }
        }

        private static float denominator(int n){
            float result = 1;
            if (n == 1)
                return 1;
            else if (n > 1)
                result = n * denominator(n - 1);
            return result;
        }

        private static float misSort(int n){
            if (n == 1)
                return 0;
            else if (n == 2)
                return 1;
            else
                return (n - 1)*(misSort(n - 1) + misSort(n - 2));
        }
    }



